A study of the chromospherically active binaries UX Fornacis and AG Doradus
A. Washuettl, K. G. Strassmeier
A&A 370, 218 (2001)
This paper presents a time-series spectrum analysis of the two chromospherically
active binary stars UX Fornacis and AG Doradus. To investigate the
rotational behaviour in combination with activity in the H
obtained almost 40 high-resolution, high-S/N spectra for each system. Both
binaries, UX For
and AG Dor, show H
of the primary star in absorption but
filled in by chromospheric emission while the H
line of the
secondaries appear in pure emission. Line variations were seen and are
detections but are not
linked to the orbital nor the rotational periods and seem to be erratic.
We obtained new orbital elements for both systems and use them in
combination with the Hipparcos parallax and our H
to determine absolute parameters.
We present the first Doppler image of the AG Dor primary using
line-profile variations of the FeI
The image reveals a cool polar feature and three equatorial spots with an
average surface temperature difference, photosphere minus spots, of up to
1500 K for the polar spot and
800 K for the equatorial spots.
Since AG Dor is one of the slowest rotators (
) that has ever
been Doppler imaged, we present several tests to demonstrate the external
consistency of our map.